Hox Hype

Has Macro-evolution Been Proven?

From the hype of the press release, it would seem that
evolution was finally proven once and for all and the creationists
should just give up and go home. But far from refuting creation,
the scientific evidence is completely consistent with creation!

The press release from UCSD said in part:

“Biologists at the University of California, San Diego have
uncovered the first genetic evidence that explains how large-scale
alterations to body plans were accomplished during the early evolution
of animals…. The achievement is a landmark in evolutionary
biology, not only because it shows how new animal body plans could
arise from a simple genetic mutation, but because it effectively
answers a major criticism creationists had long leveled against
evolution—the absence of a genetic mechanism that could permit
animals to introduce radical new body designs.”

Evolutionary biologists believe that the six-legged
insect body plan evolved from crustacean-like ancestors (including
creatures like shrimp) that lost the large number of legs1 Such a radical change would require mutation(s) that
result in the suppression of leg development. McGinnis and coworkers
believed that they found the mutation and the gene responsible for
this change. However, careful examination of their efforts reveals
that the situation is much more complicated.

The scientists were investigating Ubx, a Hox
gene which suppresses leg development in flies. Hox genes are master
control switches that control the body plan. Specific Hox genes may
control where the head forms, where limbs form, or a tail or even
wings. These master switches work like circuit breakers and either
turn on or turn off an array of other genes. Hox genes can be expressed
in abnormal locations and either prevent development of structures
or promote their development in very unusual places. For example
Pax-6 expression controls the development of eyes. A fly with abnormal
expression could form an eye on a leg, the antenna or even abdomen.2

The researchers found that the Ubx gene from a fly completely
prevented leg development while the same gene from Artemia,
a brine shrimp, only suppressed leg development 15%. They then mutated
the Artemia Ubx gene and found that this version was much more
effective at blocking leg formation. They postulated that such a
mutation probably occurred in the crustaceans that were the ancestors
of six-legged insects.3

The fact that scientists can significantly alter the
body plan does not prove macro-evolution nor does it refute creation.
Successful macro-evolution requires the addition of NEW information
and NEW genes that produce NEW proteins that are found in NEW organs
and systems.

For example, a single mutation that might prevent legs from forming
is much different from a mutation that produces legs in the first
place. Making a leg would require a large number of different genes
present simultaneously. Moreover, where do the wings come from? Just
because an organism loses a few legs doesn’t convert a shrimp-like
creature into a fly. Since crustaceans don’t have wings, where
does the information come from to make wings in flies?

Having the wings themselves is not even enough. Researchers
in another study have found that the subcellular location of metabolic
enzymes is important for the functional muscle contraction required
for flight.4 Indeed, the metabolic enzymes must be in very close
proximity with the cytoskeletal proteins that are involved in muscle
contraction. If the enzymes are not in the exact location in which
they are needed within the cell, the flies cannot fly. This study
bears out the fact that “the presence of active enzymes in the
cell is not sufficient for muscle function; colocalization of the
enzymes is required.” It also “…requires a highly
organized cellular system.”

Therefore, changes in body plan—no matter how dramatic—do
not automatically prove macro-evolution. Losing structures, or misplacing
their development, should not be equated with the increased information
that is needed to form novel structures and cellular systems.

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Answers in Genesis is an apologetics ministry, dedicated to helping Christians defend their faith and proclaim the gospel of Jesus Christ effectively. We focus on providing answers to questions about the Bible—particularly the book of Genesis—regarding key issues such as creation, evolution, science, and the age of the earth.